The KDE Look and Feel Project is a GPL-licenced Swing pluggable look and feel which uses Qt and KDE for the drawing of widgets. KDE Look and Feel implements most of the Java Look and Feel API including dialogs (ColorChooser, FileChooser, etc.).

While Sun is finally prioritizing Java on the desktop (Java 1.5 and the forthcoming 1.6 have made big speed optimzations and appearence enhancements to Swing), Java/Swing still need to improve. It's still noticably slower (particularily with long start up times), and the default "Metal" theme is still ugly as sin (and looks alien to the local environment), and anti-aliasing fonts and sub-pixel hinting is still not there (making it look like crap on LCD screens).

Newer Swing themes look better than metal (the default theme in NetBeans looks great). But for whatever reason, "Metal" is still the default. If I understand correctly, Swing uses "Metal" if not otherwise directed, or if it can't find the right theme to blend with the native environment.

This can't continue, if Sun, or the Java world in general, wants Java to succeed on the desktop. Perhaps this is due to Sun being mostly a server company.

By default, Java/Swing has to look fantastic, and be acceptably fast. Otherwise, end users will reject any desktop app written in Java, period.

A QT (or GTK) binding for Swing could improve things dramtically. The screenshots show it as looking just like a native QT/KDE app. And there is the added bonus of QT being very adaptable to the local environment - it can look just like a native Windows app, for instance.

I like Java for a lot of things. I would also like it to be good for GUI development. It's improving, but still has a long way to go. Swing is getting better, and SWT has potential (using Java wrappers around the native GUI toolkit), but SWT is not as easy to deploy.

As far as I know the default theme in 1.5 is not Metal, but Ocean, which is the blue-ish type you probably see in the latest Netbeans. Metal was a specific 1.4 l&f.
Of course another good theme site for Java is: http://www.javootoo.com/
Overall I think the Java UI is improving quite a bit, Ocean doesn't look half as bad as Metal, and a lot of the native skins are fairly good.